[Intel-gfx] [PATCH 1/4] drm/i915: Increase PSR Idle Frame to 2.

[Daniel Vetter]

On Thu, Sep 04, 2014 at 10:55:16AM +0300, Ville Syrjälä wrote:
> On Wed, Sep 03, 2014 at 10:49:56PM -0400, Rodrigo Vivi wrote:
> > With Software tracking we are going to PSR sooner than we should and staying
> > with blank screens in many cases.
> > 
> > Using 2 identical frames to detect idleness is safier.
> 
> This idle frame detection still depends of FBC right?
> 
> I believe if we want to go for full sw tracking on HSW/BDW we need to
> use the debug register to force PSR entry/exit.

Currently the sw tracking relies upon 1 additional full upload happening
after the flush, which hopefully should magically happen if we have just 1
idle frame.

If we'd completely switch to sw tracking we'd need to set up a vblank
worker to disable psr after the next vblank, which would comlicate the
code I think.
-Daniel

> 
> > 
> > Discovered and validated with refactored igt/kms_sink_psr_crc.
> > 
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index f79473b..a796831 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1813,7 +1813,7 @@ static void intel_edp_psr_enable_source(struct intel_dp *intel_dp)
> >  	struct drm_device *dev = dig_port->base.base.dev;
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> >  	uint32_t max_sleep_time = 0x1f;
> > -	uint32_t idle_frames = 1;
> > +	uint32_t idle_frames = 2;
> >  	uint32_t val = 0x0;
> >  	const uint32_t link_entry_time = EDP_PSR_MIN_LINK_ENTRY_TIME_8_LINES;
> >  	bool only_standby = false;
> > -- 
> > 1.9.3
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
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> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch